gcc/fixinc/server.c

   1
   2 /*
   3  *  server.c  Set up and handle communications with a server process.
   4  *
   5  *  Server Handling copyright 1992-1999 The Free Software Foundation
   6  *
   7  *  Server Handling is free software.
   8  *  You may redistribute it and/or modify it under the terms of the
   9  *  GNU General Public License, as published by the Free Software
  10  *  Foundation; either version 2, or (at your option) any later version.
  11  *
  12  *  Server Handling is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with Server Handling.  See the file "COPYING".  If not,
  19  *  write to:  The Free Software Foundation, Inc.,
  20  *             59 Temple Place - Suite 330,
  21  *             Boston,  MA  02111-1307, USA.
  22  *
  23  * As a special exception, The Free Software Foundation gives
  24  * permission for additional uses of the text contained in his release
  25  * of ServerHandler.
  26  *
  27  * The exception is that, if you link the ServerHandler library with other
  28  * files to produce an executable, this does not by itself cause the
  29  * resulting executable to be covered by the GNU General Public License.
  30  * Your use of that executable is in no way restricted on account of
  31  * linking the ServerHandler library code into it.
  32  *
  33  * This exception does not however invalidate any other reasons why
  34  * the executable file might be covered by the GNU General Public License.
  35  *
  36  * This exception applies only to the code released by The Free
  37  * Software Foundation under the name ServerHandler.  If you copy code
  38  * from other sources under the General Public License into a copy of
  39  * ServerHandler, as the General Public License permits, the exception
  40  * does not apply to the code that you add in this way.  To avoid
  41  * misleading anyone as to the status of such modified files, you must
  42  * delete this exception notice from them.
  43  *
  44  * If you write modifications of your own for ServerHandler, it is your
  45  * choice whether to permit this exception to apply to your modifications.
  46  * If you do not wish that, delete this exception notice.
  47  */
  48 #include "auto-host.h"
  49
  50 #include "gansidecl.h"
  51 #include "system.h"
  52 #include <signal.h>
  53
  54 #include "server.h"
  55
  56 /* If this particular system's header files define the macro `MAXPATHLEN',
  57    we happily take advantage of it; otherwise we use a value which ought
  58    to be large enough.  */
  59 #ifndef MAXPATHLEN
  60 # define MAXPATHLEN     4096
  61 #endif
  62
  63 #ifndef STDIN_FILENO
  64 # define STDIN_FILENO   0
  65 #endif
  66 #ifndef STDOUT_FILENO
  67 # define STDOUT_FILENO  1
  68 #endif
  69
  70 #ifdef DEBUG
  71 #define STATIC
  72 #else
  73 #define STATIC static
  74 #endif
  75 #ifndef tSCC
  76 #define tSCC static const char
  77 #endif
  78 #ifndef NUL
  79 #define NUL '\0'
  80 #endif
  81
  82 #if !defined(volatile) && !defined(HAVE_VOLATILE)
  83 # define volatile
  84 #endif
  85
  86 STATIC volatile t_bool read_pipe_timeout;
  87 STATIC pid_t server_master_pid = NOPROCESS;
  88
  89 static t_pchar def_args[] =
  90 { (char *) NULL, (char *) NULL };
  91 STATIC t_pf_pair server_pair =
  92 { (FILE *) NULL, (FILE *) NULL };
  93 STATIC pid_t server_id = NULLPROCESS;
  94 /*
  95  *  Arbitrary text that should not be found in the shell output.
  96  *  It must be a single line and appear verbatim at the start of
  97  *  the terminating output line.
  98  */
  99 tSCC z_done[] = "ShElL-OuTpUt-HaS-bEeN-cOmPlEtEd";
 100 STATIC t_pchar p_cur_dir = (char *) NULL;
 101
 102 /*
 103  *  load_data
 104  *
 105  *  Read data from a file pointer (a pipe to a process in this context)
 106  *  until we either get EOF or we get a marker line back.
 107  *  The read data are stored in a malloc-ed string that is truncated
 108  *  to size at the end.  Input is assumed to be an ASCII string.
 109  */
 110 static char *load_data PARAMS ((FILE *));
 111 static char *
 112 load_data (fp)
 113      FILE *fp;
 114 {
 115   char *pz_text;
 116   size_t text_size;
 117   char *pz_scan;
 118   char z_line[1024];
 119   t_bool got_done = BOOL_FALSE;
 120
 121   text_size = sizeof (z_line) * 2;
 122   pz_scan = pz_text = malloc (text_size);
 123
 124   if (pz_text == (char *) NULL)
 125     return (char *) NULL;
 126
 127   for (;;)
 128     {
 129       size_t used_ct;
 130
 131       alarm (10);
 132       read_pipe_timeout = BOOL_FALSE;
 133       if (fgets (z_line, sizeof (z_line), fp) == (char *) NULL)
 134         break;
 135
 136       if (strncmp (z_line, z_done, sizeof (z_done) - 1) == 0)
 137         {
 138           got_done = BOOL_TRUE;
 139           break;
 140         }
 141
 142       strcpy (pz_scan, z_line);
 143       pz_scan += strlen (z_line);
 144       used_ct = (size_t) (pz_scan - pz_text);
 145
 146       if (text_size - used_ct < sizeof (z_line))
 147         {
 148           size_t off = (size_t) (pz_scan - pz_text);
 149           void *p;
 150
 151           text_size += 4096;
 152           p = realloc ((void *) pz_text, text_size);
 153           if (p == (void *) NULL)
 154             {
 155               fprintf (stderr, "Failed to get 0x%08lX bytes\n",
 156                       (long) text_size);
 157               free ((void *) pz_text);
 158               return (char *) NULL;
 159             }
 160           pz_text = (char *) p;
 161           pz_scan = pz_text + off;
 162         }
 163     }
 164
 165   alarm (0);
 166   if (read_pipe_timeout || ! got_done)
 167     {
 168       free ((void *) pz_text);
 169       return (char *) NULL;
 170     }
 171
 172   while ((pz_scan > pz_text) && ISSPACE (pz_scan[-1]))
 173     pz_scan--;
 174   *pz_scan = NUL;
 175   return realloc ((void *) pz_text, strlen (pz_text) + 1);
 176 }
 177
 178
 179 /*
 180  *  close_server
 181  *
 182  *  Make certain the server process is dead, close the
 183  *  pipes to it and from it, finally NULL out the file pointers
 184  */
 185 void
 186 close_server ()
 187 {
 188   if (  (server_id != NULLPROCESS)
 189      && (server_master_pid == getpid ()))
 190     {
 191       kill ((pid_t) server_id, SIGKILL);
 192       server_id = NULLPROCESS;
 193       server_master_pid = NOPROCESS;
 194       fclose (server_pair.pf_read);
 195       fclose (server_pair.pf_write);
 196       server_pair.pf_read = server_pair.pf_write = (FILE *) NULL;
 197     }
 198 }
 199
 200 /*
 201  *  sig_handler really only handles the timeout and pipe signals.
 202  *  This ensures that we do not wait forever on a request
 203  *  to our server, and also that if the server dies, we do not
 204  *  die from a sigpipe problem.
 205  */
 206 static void sig_handler PARAMS ((int));
 207 static void
 208 sig_handler (signo)
 209      int signo ATTRIBUTE_UNUSED;
 210 {
 211 #ifdef DEBUG
 212   /* FIXME: this is illegal to do in a signal handler.  */
 213   fprintf (stderr,
 214           "fixincl ERROR:  sig_handler: killed pid %ld due to %s\n",
 215           (long) server_id, signo == SIGPIPE ? "SIGPIPE" : "SIGALRM");
 216 #endif
 217   close_server ();
 218   read_pipe_timeout = BOOL_TRUE;
 219 }
 220
 221
 222 /*
 223  *  server_setup  Establish the signal handler for PIPE and ALARM.
 224  *  Also establishes the current directory to give to the
 225  *  server process at the start of every server command.
 226  */
 227 static void server_setup PARAMS ((void));
 228 static void
 229 server_setup ()
 230 {
 231   static int atexit_done = 0;
 232
 233   if (atexit_done++ == 0)
 234     atexit (close_server);
 235   else
 236     fputs ("NOTE: server restarted\n", stderr);
 237
 238   server_master_pid = getpid ();
 239
 240   signal (SIGPIPE, sig_handler);
 241   signal (SIGALRM, sig_handler);
 242
 243   fputs ("trap : 1\n", server_pair.pf_write);
 244   fflush (server_pair.pf_write);
 245   p_cur_dir = getcwd ((char *) NULL, MAXPATHLEN + 1);
 246 }
 247
 248 /*
 249  *  find_shell
 250  *
 251  *  Locate a shell suitable for use.  For various reasons
 252  *  (like the use of "trap" in server_setup(), it must be a
 253  *  Bourne-like shell.
 254  *
 255  *  Most of the time, /bin/sh is preferred, but sometimes
 256  *  it's quite broken (like on Ultrix).  autoconf lets you
 257  *  override with $CONFIG_SHELL, so we do the same.
 258  */
 259
 260 static char *find_shell PARAMS ((void));
 261 static char *
 262 find_shell ()
 263 {
 264   char * shell = getenv ("CONFIG_SHELL");
 265   if (shell)
 266     return shell;
 267
 268   return "/bin/sh";
 269 }
 270
 271
 272 /*
 273  *  run_shell
 274  *
 275  *  Run a shell command on the server.  The command string
 276  *  passed in is wrapped inside the sequence:
 277  *
 278  *     cd <original directory>
 279  *     <command string>
 280  *     echo
 281  *     echo <end-of-command-marker>
 282  *
 283  *  This ensures that all commands start at a known place in
 284  *  the directory structure, that any incomplete output lines
 285  *  are completed and that our special marker sequence appears on
 286  *  a line by itself.  We have chosen a marker that is
 287  *  excessively unlikely to be reproduced in normal output:
 288  *
 289  *     "ShElL-OuTpUt-HaS-bEeN-cOmPlEtEd"
 290  */
 291 char *
 292 run_shell (pz_cmd)
 293      const char *pz_cmd;
 294 {
 295   tSCC zNoServer[] = "Server not running, cannot run:\n%s\n\n";
 296   t_bool retry = BOOL_TRUE;
 297
 298  do_retry:
 299   /*  IF the shell server process is not running yet,
 300       THEN try to start it.  */
 301   if (server_id == NULLPROCESS)
 302     {
 303       def_args[0] = find_shell ();
 304
 305       server_id = proc2_fopen (&server_pair, def_args);
 306       if (server_id > 0)
 307         server_setup ();
 308     }
 309
 310   /*  IF it is still not running, THEN return the nil string.  */
 311   if (server_id <= 0)
 312     {
 313       char *pz = (char *) malloc (1);
 314       fprintf (stderr, zNoServer, pz_cmd);
 315       if (pz != (char *) NULL)
 316         *pz = '\0';
 317       return pz;
 318     }
 319
 320   /*  Make sure the process will pay attention to us, send the
 321      supplied command, and then have it output a special marker that
 322      we can find.  */
 323   fprintf (server_pair.pf_write, "cd %s\n%s\n\necho\necho %s\n",
 324            p_cur_dir, pz_cmd, z_done);
 325   fflush (server_pair.pf_write);
 326
 327   /*  IF the server died and we received a SIGPIPE,
 328       THEN return an empty string.  */
 329   if (server_id == NULLPROCESS)
 330     {
 331       char *pz = (char *) malloc (1);
 332       fprintf (stderr, zNoServer, pz_cmd);
 333       if (pz != (char *) NULL)
 334         *pz = '\0';
 335       return pz;
 336     }
 337
 338   /*  Now try to read back all the data.  If we fail due to either a
 339      sigpipe or sigalrm (timeout), we will return the nil string.  */
 340   {
 341     char *pz = load_data (server_pair.pf_read);
 342
 343     if (pz == (char *) NULL)
 344       {
 345         close_server ();
 346
 347         if (retry)
 348           {
 349             retry = BOOL_FALSE;
 350             goto do_retry;
 351           }
 352
 353         fprintf (stderr, "CLOSING SHELL SERVER - command failure:\n\t%s\n",
 354                  pz_cmd);
 355         pz = (char *) malloc (1);
 356         if (pz != (char *) NULL)
 357           *pz = '\0';
 358       }
 359 #ifdef DEBUG
 360     fprintf( stderr, "run_shell command success:  %s\n", pz );
 361 #endif
 362     return pz;
 363   }
 364 }